In this family STEM activity, students take an inside look at the polymer in diapers that makes them absorbent.

Just Add Water

What do astronauts and babies have in common? They both rely, at times, on diaper-like solutions to keep them dry. When it comes to how a diaper absorbs liquid and keeps moisture away from the body, there is serious science at work. With a family-friendly science activity, kids can take a closer look at what happens inside a diaper when the diaper gets wet.

If you have ever held a wet diaper, you may have noticed that it seems to be filled with a gel-like substance. When the diaper is dry, however, it is thin and light-weight. The key is sodium polyacrylate, a powdered polymer that can absorb over 300 times its weight in water.

With a few diapers, food coloring, water, and some clear cups, families can experiment to see what happens when sodium polyacrylate gets wet. What happens if you increase or decrease the amount of sodium polyacrylate? How much of the chemical is needed for a diaper to be effective? Cut open a few diapers, shake the powder out, and put diaper science to the test!

You can find this page online at: https://www.sciencebuddies.org/blog/diaper-duty-science

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